The demand for frozen foods is driven by the ever changing consumers and their lifestyle. Consumers are spending less time per day preparing meals at home, and their time-starved, fast-paced lifestyles have them searching for alternative meal solutions. Changes in demographics have also created a need for good tasting, affordable, healthy, yet convenient food. However, frozen foods pass through numerous handlers during the distribution process (the “cold chain”). If a frozen food product is not properly handled throughout each link in the cold chain, i.e. it is exposed to an environmental condition of improper temperature, the thawing of the perishable frozen food will cause the quality and taste of the frozen food to deteriorate.
It is doubtful and difficult to prove that the frozen food products are kept in a proper temperature range during the cold chain. The failing of providing substantial data of temperature control during shipment by the frozen food distributors helps to create reasonable doubt about the hygiene of frozen food, especially when there is disadvantageous news about the quality of food product. Without the data of temperature control, it is difficult to specify exactly which part of the cold chain is the one to blame while the quality problem of the shipped frozen food occurs.
As seen in FIG. 1, as a food product 10 leaves a kitchen 15, it may be shipped by a transportation means like a ship 12, a truck 14, or an airplane 15, to be distributed to a retailer 15. The quality problem of the shipped frozen food might occur during the distribution if the temperature control of any one of the links in the cold chain of FIG. 1 is failed. Thus, how to control the hygiene of frozen food during the shipment in the cold chain becomes an urgent problem that has to be overcome.
Recently, as the advance of RFID technology, there are some patented RFID devices that can be used in the field of food hygiene control, such as the RFID devices disclosed in R.O.C. Pat. No. 460640, entitled “Method, Electronic Tag and System for Reporting Dynamic Properties of a Product Using Radio Frequency Identification Device Technology”, in U.S. Pat. No. 6,294,997, entitled “RFID Tag Having Timing and Environment Modules”, in U.S. Published Application No. 2004/0100380, entitled “RFID System and Method for Tracking Food Freshness”, and in U.S. Published Application No. 2004/0041714, entitled “RFID temperature device and method”.
In the R.O.C. Pat. No. 460640, an electronic tag equipped with a sensor is provided, which can determine dynamic properties of a product when the tag is activated, The dynamic properties of the product are then either further processed into other dynamic properties. In any even either the former or the latter dynamic properties are then transmitted from the tag. Such dynamic properties could be the temperature of a product or the expiration data of the product derived from periodic measurements of the temperature of the product.
In U.S. Pat. No. 6,294,997, an RFID tag is provided with a timing module to measure elapsed time and an environment module to detect certain environmental conditions. The RFID tag includes a transmitter/receiver, memory module, antenna module, converter, and the timing and environment modules. In an embodiment of the invention, the timing module enables the user, upon interrogating the RFID tag, to determine the precise length of time from the previous charge of the RFID tag. The environment module enables the user to determine how long the RFID tag has been exposed to certain environmental conditions that have been pre-defined by the user.
In U.S. Published Application No. 2004/0100380, a method is provided for tracking the freshness or expiration dates of food products put into storage. The food products placed into storage are provided with smart tags, the smart tags containing food product information regarding the freshness or expiration date of the food product. The food products are scanned with a smart tag scanner prior to placing the products into storage, the scanner configured to retrieve the food product information from the smart tags. The user may be alerted if the retrieved information indicates that the food product being placed into storage has expired or is no longer fresh. The food products are placed in storage, and the user may be alerted when any of stored products have expired or are no longer fresh.
In U.S. Published Application No. 2004/0041714, a remote communication device is provided that receives temperature indicia concerning a container and/or its contents and communicates such temperature indicia along with an identification indicia to a reader. The remote communication device can measure and communicate temperature indicia associated with a container in a periodic manner. The remote communication device can also measure and communicate temperature indicia associated with a container when such temperature indicia exceed a certain minimum or maximum threshold temperature. The remote communication device can also include power circuitry to store energy when energized in the range of an interrogation reader so that the remote communication device can be powered for temperature indicia measurements when not in the range of an interrogation reader.
The operating principle of the abovementioned prior-art RFID devices is that the RFID tag equipped with batteries and sensors is configured to record the length of time from the previous charge of the RFID tag and how long the RFID tag has been exposed to certain environmental conditions. The kind of the abovementioned prior-art RFID devices relay on the batteries arranged therein for providing power to the environment module to detect certain environmental conditions. Once the power reserved in the battery is low that is not detected in time, the normal recording and detecting of the environment module can be adversely affect that even cause previously recorded environmental data to loss. In addition, the cost of the abovementioned active RFID devices is high that the popularization of the active RFID devices might not be feasible. Besides, the abovementioned prior-art RFID devices still unable to provide substantial data of temperature control during shipment to be access easily by consumers that the reasonable doubt about the hygiene of frozen food still can not be avoided.
Therefore, it is required to have a RFID system capable of monitoring food hygiene during the shipment.